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Pesticide Topics

by: Victor Schaefer Sr.

Pesticide Topics Entom 558

Victor Schaefer Sr.
GPA 3.75

Allan Felsot

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Allan Felsot
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This 37 page Class Notes was uploaded by Victor Schaefer Sr. on Thursday September 17, 2015. The Class Notes belongs to Entom 558 at Washington State University taught by Allan Felsot in Fall. Since its upload, it has received 66 views. For similar materials see /class/205991/entom-558-washington-state-university in Entomology at Washington State University.

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Date Created: 09/17/15
ENTOM 558 Pesticide Topics Fall 2005 October 31 2005 Lecturer Allan Felsot Department of Entomology Food amp Environmental Quality Lab WSU TriCities Campus afelsottricity wsu edu Pesticide Benefits amp Costs Pesticide Regulation Evolution of Laws Food Quality Protection Act Overview Part 1 A Consideration of Pesticide Benefits and Utility I Introduction A Any consideration of pesticide regulations will be better informed by first considering the question Why Use Pesticides 1 N Indeed listening and reading to certain advocacy groups one would think that crop protection was a simple matter for which there was already available an off the shelf non pesticide technology a However such a simplistic black or white notion belies the complexity of any agroecosystem b Furthermore the goal of crop protection seems to have moved from ecological management ie reduce competition between pests and humans to eliminate pesticide use In developed countries the focus is on agricultural pests and pesticides perhaps because they seemed to have public health pests tamed Yet in many countries public health pests are the major threat and the context of why use a pesticide takes on a different meaning II Definitions A Before considering why pesticide use may or may not be indispensable consider the regulatory definition of a pesticide and how it differs from fertilizers P3 O Fertilizer Macro and trace nutrients added to soil or in some cases to plant foliage to maximize the production of plants crop ornamentals lawns etc Not regulated by EPA with regards to labeling requirements or application rates requires no permits or licenses to make an application a However consequences of use of any fertilizer as it pertains to effects on water quality will be under the jurisdiction of the EPA through both the Safe Drinking Water Act and the Clean Water Act States may regulate labeling of fertilizers to protect against adulteration which can include putting in too much or too little of a nutrient a Canada regulates the heavy metal content of fertilizers in addition to the essential elements b WA State now has regulations for maximum permissible heavy metal content modeled after the Canadian standards Pesticide defined by laW the Federal Insecticide Fungicide and Rodenticide Act FIFRA passed 1947 Title 40 CFR Code of Federal Regulations Section 1623 1 ENTOM558 Lect 103105 Benefits Regsdoc Any substance or mixture of substances intended for preventing destroying repelling or mitigating any pest insect rodent plant or animal life or viruses Page 1 of 29 ENTOM 558 E 4 Pesticide Topics Fall 2005 bacteria or other microorganisms except viruses bacteria or other microorganisms on or in living man or other animals which the Administrator declares to be a pest in other words a pest is a Any insect rodent nematode fungus weed or b Any other form of terrestrial plant or animal life or virus bacteria or other microorganism except viruses bacteria or other micro organisms on or in living man or other living animals which the EPA administrator declares to be a pest Any substance or mixture of substances intended for use as a plant regulator defoliant or desiccant Definition in 1 therefore does include disinfectants a Indeed if you look on a can of Lysol you will see the active ingredient the older cans contained orthophenylphenol with an EPA Registration No which must accompany all approved pesticide active ingredients The major groups thus include herbicides insecticides also acaricides amp nematicides fungicides plant growth 39 39 39 391 piscicides and disinfectants a Note that pesticides generally have several nomenclatural designations 1 Common chemical name the technical active ingredient a endosulfan MW 2 4069 2 Formulation names containing the active ingredient commercial product a Thiodan Thiofur and others 3 Official chemical nomenclature ie approved by the IUPAC International Union of Pure and Applied Chemistry 1 a 67891010 hexachloro 155a699a hexahydro 69 methano 243 benzodioxathiepin 3 oxide HOLY COW III The Rationale for Use of Agrichemical Technology Lies in the Nature of Agroecosystems and Associated Pests A Natural ecosystems are self sustaining by virtue of their biotic diversity naturally adapted to the physical environment such diversity allows the system to respond to perturbations Furthermore the soil stores plant nutrients which are continually recycled throughout the ecosystem 53 ENTOM558 Lect 103105 Benefits Regsdoc 1 For example the ecosystems around Mt St Helen have been re establishing because of the inherent genetic diversity that was present in the system Agroecosystems have significantly less diversity therefore they cannot adapt easily ie economically to perturbations in the system N Keep in mind that agroecosystems are designed to maximize profit for the grower thus many systems are monocultures or bicultures for example strip farming where crops are grown in alternating rows of variable number Thus agroecosystems are designed to have less diversity a Row crops and vegetable crops are disturbed at least annually b Fruit crops are disturbed very infrequently unless the areas between treesbushesvines are cultivated It is easier for one species to become dominant and overwhelm other organisms in the system Page 2 of 29 ENTOM 558 3 4 Pesticide Topics Fall 2005 Modern cropping systems tend to be monocultures with very limited genetic diversity therefore they are very susceptible to perturbations by organisms that use the crop as a food source Nutrients are continually removed from the system by the annual harvesting of plant material C Pests can be native to ecosystems that have been altered to grow crops or they can be incidentally imported from other continents In the first case the pest has a readily abundant food supply and its population will grow quite readily especially if mortality factors do not adequately suppress its population a Mortality factors include natural enemies predators and parasitoids diseases adverse meteorological conditions starvation b An example of a native pest is the northern corn rootworm which feeds on the roots of corn grown in the northern tier of the Corn Belt In the second case natural mortality factors especially that related to natural enemies may not be present or operational in the new ecosystems to which the immigrant organism has arrived thus immigrant or exotic organisms easily become established for example the Gypsy moth attacking forests of the northeast the Colorado potato beetle attacking potatoes grown just about everywhere in the US IV The Nature of Agroecosystems and Human Objectives Demand Some Form of Management Intervention The conflict between the economic value of a crop and its susceptibility to damage from a burgeoning pest population demands the need for management of both the crop and the pest A ENTOM558 Lect 103105 Benefits Regsdoc The continual removal of nutrients from the soil by harvesting a crop ie and the comparatively short time interval between successive cropping needs demands the addition of readily available nutrients to grow succeeding crops The intentional addition of fertilizers and pesticides to cropping systems has been occurring for hundreds of years suggesting that ecosystem management is not a recent cultural attribute 1 History of Pesticides reference G W Ware 1983 Pesticides Theory amp Application W H Freeman amp Co San Francisco pp 11 13 some notable highlights a 1200 BC biblical armies salt and ash the fields of the conquered first reported use of nonselective herbicides b 1000 BC Homer refers to sulfur used in fumigation and other forms of pest control c 100 BC The Romans apply hellebore lily family contains alkaloids for the control of rats mice and insects d 70 AD Pliny the Elder reports pest control practices from Greek literature of the preceding three centuries for ex 1 Touch the top of an apple tree with the gall of a green lizard for protection against caterpillars and rot e 900 AD Chinese use arsenic to control garden insects f 1690 AD Tobacco extracts used as contact insecticide Page 3 of 29 ENTOM 558 Pesuclde Toplcs Fall 2005 1787 AD Soap rnenuoned as msecuclde turpenune emulslon recommended to klll and repel msecll 1800 AD Perslan louse powder actually pyrethrlunn known to the Caucasus g h for scale lnsect Con OL l 1 48 AD Derns rotenone reported belng used In lnsectcontrol 111 Asla 1857 AD Pans green acetormitaralsemte of coppe 1 Flrstused as a green plgrnentln palnts tabnc and mil papers 2 Used In Colorado potato beetle control and mosqulto control k 1892 AD Lead arsenate rust prepared and used to control gypsy moLh tlrstuse oxldauve phosphorylauon 2 h u yl would funcuon 111 natural ecosystems but are absent from agroecosysterns v Role of Agricultural Chemicals in Crop Production amp protection Fuel to consldenng the specltlc bene ts of pesucldes and femllzels conslder tarnnland uullzauon and producuon changes relauye to populauon changes after World War ll Flgure 1 crop ere a hmested 20 t l 1 i A39IL mu hm hm mu NU um Wm quotHA mm Flgure 1 Trends though 19501n crop ploducLlon acreage for ploducLlon and populaucn growth ENTOMSSX Lect103105 Beneflts Regs doc Page 4 df29 ENTOM 558 Pesticide Topics Fall 2005 B Consider the estimated amounts of crop losses despite the use of pesticides 1 Estimates of d r rli ea KiuNnnh and Penn I A 39 1987 were 113 of crop production at a cost of 14 billion James et al 1991 a The total cost of fungicides for controlling diseases was estimated as 3 of the total loss dueto diseme 2 An annual economic loss due to weeds was estimated m 9 billion during 197571979 Chandler 1991 C Bene ts of Pesticides amp Fertilizers 1 Until August 1996 the bene ts of pesticides were permitted consideration FJFRA Federal Insecticide amp Fungicide Act the main statute governing pesticide J n d memir A m FFDCA had been the only environmental law governing chemical technology allowing an msessment or balancing of the benefits and risks a During August 1996 FJFRA and FFDCA were amended by the Food Quality Protection Act FQPA The FQPA severely restricted consideration of benefits when registering a pesticide discussed below 2 The use of pesticides and fertilizers can be empiriwlly be shown to be correlated with yield incremes a During 195171960 insects caused an estimated annual loss worth 68 billion cited in Hayes and Laws 1991 Handbook of Pesticide Toxicology vol 1 General Principles Academic Press Inc 1 u r u 139 39 39J r 39 hybrid seed but really took off once fertilizer and later insecticide use incremed graph copied from Hayes amp Laws 1991 Hybrid Seed Use a fertiliz er m at vacn Pllmrlivm w mu V insecticide J t i 39 Iglp Iwu ma mm mm IQED a a ENTOM558 Lect 103105 Bene ts Regsdoc PageS of 29 ENTOM 558 Pesticide Topics Fall 2005 Figure 2 Trend in corn yield in relationship to hybrid seed fertilizer and insecticide use b Weeds caused average losses of 22 44 of production of soybeans corn small grain flax and forage compared with weed free or weed controlled fields of the same crops MN Agric Extension Service 1964 as cited in Hayes amp Laws 1991 H333 r39 r 5m Corn Q q 4393 391quot Effect ofWeeds on E the Production of E 3 93quot Corn and Soybeans T r 391 3 T39 quot m I quotHIE ab Soybeans um U u I I I I I I I I I I I I I I I I Cl In 13 917 513 I III I In I I ET til l Wm pp nmlcr see Figure 3 Figure 3 Yield of corn and soybeans are affected by weed density 3 Pesticides also play a major role in protection of human health for example the control of malaria or other insect vectored diseases Figure 4 In India during 1933 35 there were 100 million cases of malaria in 1966 long after the use of DDT began there were 150 thousand cases translated to dollars this was a change from a 13 billion dollar economic loss to a 2 million dollar loss from Hayes amp Laws 1991 a ENTOM558 Lect 103105 Benefits Regsdoc Page 6 of 29 ENTOM 558 Pesticide Topics Fall 2005 ilI 21011 mm 25m Anovhelinemosauitoesmonth 1nm from capturing 51T ELIIlfJ 450 3 441539 5 I ll 1 E r I 5 If U I I 239m I 1 1 BUEREIEIEEF39IIEJE 18 I39ll 5quot QIUI D QIEIIOIC39 n 15 l 194 l was 1 1m Malaria cases 1000 DDT Spraying Post 1945 Figure 4 Effect of the DDT spraying campaign in India on Anopheline mosquito population and incidence of malaria 4 More recent economic analyses for crops grown in California show significant income losses when pesticides are banned Zilberman et al 1991 a For example the yearly cost to growers and consumers in banning use of parathion on lettuce in California was calculated to be 484 million dollars note nonusers of parathion who grow lettuce actually gained because of higher prices but consumers still lose An economic analysis based partly on stakeholder surveys and modeling predicted significant losses in vegetable and fruit production if pesticide use was reduced either by 50 or completely eliminated Knutson et al 1993 Figure 5 Another economic analysis Taylor 1995 estimated per acre yield decreases of 25 and 60 for respectively 50 and 100 pesticide use reduction The corresponding costs of production were estimated to increase by 30 and 75 for 50 and 100 pesticide elimination respectively The wholesale price increase estimates varied by U 0 ENTOM558 Lect 103105 Benefits Regsdoc Page 7 of 29 ENTOM 558 Pesticide Topics Fall 2005 commodity ranging from 919 for a 50 pesticide reduction scenario and from 297 65 for a 100 elimination Also domestic use of fruit and vegetables were estimated to decline by 477 50 reduction or 7723 for 100 elimination With a total ban on pesticides acreage required for production of fruit and vegetables was estimated to increase by 25 million acres Estimated Effects of Reduction in Pesticide Use vegetables fruit fresh processed fresh processed Yield Reduction 40 I 50 reduction 2 zero use Knutsan etal1993 Figure 5 Estimated loss in yield for two pesticide use scenarios 50 reduction and zero use D Pesticides have certain advantages in crop protection that make their use very convenient efficient and costieffective ie the number one tool in crop protection from Metcalf amp Luckmann 1975 1 For most cropping systems and in some cases insectivectored diseases pesticides are the only practical technology ie other technologies are not available unproved or do not work efficiently 2 Pesticides have rapid curative action in preventing loss of crop yield or protecting humananimal healt a Thus they can be used in an emergency b Furthermore modem pesticides are biodegradable thus they disappear from the agroecosystem at least the residues become toxicologically insignificanta point of some controversy 3 Pesticides offer a wide range of properties uses and methods of application to pest situations a Many different types of products chemistry some selective some broad spectrum b Many modes of application and formulations available 4 Economic returnicost ratio for pesticide use is generally favorable ENTOM558 Lect 103105 Bene ts Regsdoc Page 8 of 29 ENTOM 558 Pesticide Topics Fall 2005 a Depending on the crop this ratio can range from 4 29 returned for every 1 spent b The economic return cost ratio goes down when 1 Price of crop decreases but pesticide cost is fixed 2 A product is used and pest populations are not at a level that will cause economic damage 3 Development costs for a new product are high E Given the benefits and advantages of pesticides have we been suckered into some kind of treadmill 1 Costs of Pesticide Development and Registration a RampD costs have been estimated to be over 70 million 1 Furthermore once the pesticide has been discovered and the required tests conducted EPA may require 24 38 months to review the request for registration Racke 2003 b Reregistration Fee estimated at 150000 per product ie not active ingredient but formulated product does not include cost of any new studies that may be required c Product maintenance fee estimated at 35000 d Economics of pesticide development and marketing Leng 1991 1 It may take 15 years from discovery for a pesticide product to attain a positive cash flow by year 20 after discovery the patent would have expired the patent is usually obtained around 3 years after discovery of a new product 2 Has pesticide use shot up as one might predict if we were on a treadmill a Generalizations are dangerous 1 There is a tendency to equate the amount of pesticide use with hazard but these are not evenly remotely related if once considers basic toxicological and risk assessment principles a For example the most heavily used pesticide in orchard crops are petroleum oils largely used as a dormant spray for insect control These same compounds are certified for organic agriculture and they are even used for post bloom control of pests in organic orchards b Amounts of pesticides used will vary depending on acreage cropped weather and pest outbreaks c For trends in pesticide use over the last decade specifically for field crops corn cotton potatoes rice soybeans and wheat and various fruit and vegetable crops see the NASS National Agricultural Statistical Service web site httpnsda mannlib mmquot ncubb see Table 1 for selected statistics d The impact of transgenic characters for pest control for example Bt toxin containing corn and cotton and Round Ready crops remains to be seen but preliminary data indicate that less insecticides are being used in cotton Overall use of herbicides may be down in soybeans but the trend was going down owing to the use of low rate herbicides ENTOM558 Lect 103105 Benefits Regsdoc Page 9 of 29 ENTOM 558 Pesticide Topics Fall 2005 Table 1 Change in acreage and pesticide use for corn potato and apple 1991 vs 2003 Data are taken from the USDA National Agricultural Statistical Service Reports URL httpusdamannlibcornelledure ortsnassrotherpcu bb Corn 1991 2003 Change Acres Planted X 106 762 727 351 Acres Treated with Herbicides 94 95 1 Pounds X 106 211 149 62 Acres Treated with Insecticides 30 29 1 Pounds X 106 233 747 1583 Potato 1991 2003 Change Acres Planted X 106 120 102 0 18 Acres Treated with Herbicides 79 91 12 Pounds X 106 22 158 062 Acres Treated with Insecticides 91 84 7 PoundsX106 31 157 153 Acres Treated with Fungicide 69 91 22 Pounds X 106 27 654 384 Acres Treated with Others Fumigants Defoliants 45 47 2 Pounds X 106 39 754 364 Apple 1991 2003 Change Acres Planted X 106 035 0305 0045 Acres Treated with Herbicides 42 42 0 Pounds X 106 031 0386 0076 Acres Treated with 39 quot 39J 99 94 5 Pounds X 106 127 93 34 Acres Treated with Fungicide 83 90 7 Pounds X 106 47 486 016 Acres Treated with Others Plant Growth Regulators Pheromones 57 20 37 Pounds X 106 007 0134 0064 VI The Down Side of Pesticide Use A Despite their benefits pesticides have limitations that make their indiscriminate use unwise 1 Noted Problems With Pesticides note the first three listings are considered by many scientists to be the most important problems the change in pesticide chemistry over the last two decades has demoted the importance of the last two listings although these are still very controversial with regard to their significance ENTOM558 Lect 103105 Benefits Regsdoc Page 10 of 29 ENTOM 558 Pesticide Topics Fall 2005 a Worker exposure and poisoning especially acute toxicity 1 Pesticide Incident Reporting and Tracking panel in WA State b Development of pest resistance limits the available control technologies 0 Reduction of natural enemies and resurgence of pest problems elevation of importance of damage by secondary pests d Adverse effects on environmental health 1 Fish bird kills 2 Bioaccumulation in food chain 3 Endocrine disruptive effects e Human health general population 1 Chronic toxicity cancer 2 A H quotM or39 quot acute B Calculating An Economic Cost Environmental and Social Costs to Pesticide Use 1 Total estimated environmental and social costs from pesticide in the US according to Pimental et al 1993 Table 2 Table 2 Estimated and social costs of VII Reconciling Pesticide Use with Environmental StewardshipThe Advent of Integrated Pest Management IPM and Sustainable Agriculture A Not long after the widespread and frequent use of DDT agricultural scientists realized it was not the miracle cure for insect problems this recognition led to the development of the concept of integrated control now known as IPM Integrated control recognized that pest control was most efficient when biological control ie natural enemies and cultural practices were integrated with chemical control however chemical control had to have certain characteristics to make it effective over the long term and environmentally safe Stern et al 1959 a Use of selective insecticides ie high toxicity to pests low toxicity to nontarget organisms 1 The ideal insecticide is one that shifts the balance back in favor of the natural enemies 9 Treating only areas where the pest natural enemy ratio is unfavorable to effectively managing the pest population ENTOM558 Lect 103105 Benefits Regsdoc Page 11 of 29 ENTOM 558 Pesticide Topics Fall 2005 c Proper timing of insecticide application apply only when pest population can cause economic loss apply only when beneficial insects like honeybees are not foraging d Use of rapidly degradable chemicals e Development of insect pathogens as insecticides B One of the key aspects of the development of integrated control and the evolution of IPM was the acquisition of the fundamental knowledge of the ecology of the agroecosystem and a detailed analysis of the population dynamics and behaviors of the pests and the natural enemies 1 Such knowledge leads to the development of economic injury levels and economic thresholds In brief for any population in an ecosystem there are dynamic fluctuations in population density over time but there is a general equilibrium position about which these populations fluctuate Figure 6 a The economic injury level EIL is the pest population density causing sufficient crop damage to prevent economic return from exceeding costs of production b The economic threshold ET is the pest population level at which control measures would be implemented to prevent the population from reaching the economic injury level Theoretically at the ET the cost of control would equal the return from implementing the control N Insect Populations are Controlled by Biotic and Environmental Factors Economic Injury Level EIL A Economic Threshold ET General Equilibrium r Position GEP Time Figure 6 Pest population dynamics in relation to the economic threshold and economic injury level Populatoin Density C Essential Elements of Integrated Pest Management defined as the practical manipulation of pest populations using sound ecological principles to keep the populations below the levels causing economic injury 1 Insect bionomics a Must correctly identify classify the pest such classification leads to a plethora of information about biology 2 Characterization of population dynamics ENTOM558 Lect 103105 Benefits Regsdoc Page 12 of 29 ENTOM 558 Pesticide Topics Fall 2005 a Development of life tables identification of all the factors affecting mortality and the magnitude of the effects 3 Development of scouting and sampling plans 4 Development of economic injury level and economic threshold 5 Development of alternative control options a Pesticides are only one too although for the vast majority of crops the most convenient and ef cient others include Biological control introduction or encouragement of natural enemies 2 Cultural control for ex crop rotation 3 Mechanical control for ex powerful vacuum systems to suck up aphids weed cultivation 4 Host plant resistance physiological traits bred into plants that resist pest damage D Ecologically Based Pest Management EBPM 1 A National Academy of Sciences report published in 1996 discussed the next evolution of IPM to EBPM 2 The report argued that IPM systems were largely centered around synthetic pesticide use but pest management needed to become more biologically centered E The Coming of Sustainable Agriculture 1 Unfortunately the term sustainable especially as applied to agriculture has become confused with no pesticide use but this is not even close to the intended meaning It has also been misperceived as big brotherism ie the government is going to tell farmers who have been quite successful thus far on how to farm or not farm a The term sustainable has become somewhat clich unfortunately there are no models for sustainable systems if past civilization were sustainable they would still be here 1 Thus we are engaged in a grand experiment All we can do is continue to learn how our universe works and develop technologies that seem consistent with long term survival not subsistence survival but survival with a high quality of life The best definition of sustainable agriculture is not a single definition at all but an operational definition ie a set of circumstances or processes National Academy of Sciences 1993 preference for use of term alternative agriculture thus alternative agriculture is any system of food or fiber production that systematically pursues the following goals a More thorough incorporation of natural processes such as nutrient cycles nitrogen fixation and pest predator relationships into the agricultural production process b Reduction in the use of off farm inputs with the greatest potential to harm the environment or the health of farmers and consumers c Greater productive use of the biological and genetic potential of plant and animal species d Improvement of the match between cropping patterns and the productive potential and physical limitations of agricultural lands to ensure long term sustainability of current production levels N ENTOM558 Lect 103105 Benefits Regsdoc Page 13 of 29 ENTOM 558 e Pesticide Topics Fall 2005 Profitable and efficient production with emphasis on improved farm management and conservation of soil water energy and biological resources 3 Some examples of practices and principles emphasized in alternative systems include a 05 f Crop rotations that mitigate weed disease insect and other pest problems increase available soil nitrogen and reduce the need for purchased fertilizers and in conjunction with conservation tillage practices reduce soil erosion IPM which reduces the need for pesticides by crop rotations scouting weather monitoring use of resistant cultivars timing of planting and biological pest controls Management systems to control weeds and improve plant health and the abilities of crops to resist insect pests and diseases Soil and water conserving tillage Animal production systems that emphasize disease prevention through health maintenance thereby reducing the need for antibiotics Genetic improvement of crops to resist insect pests and diseases and to use nutrients more effectively 4 Note most importantly that alternative systems are diversified also it is not a single system of farming practices it includes a spectrum of farming systems ranging from organic systems that attempt to use no purchased synthetic chemical inputs to those involving the prudent use of pesticides or antibiotics to control specific pest or diseases F To determine the potential role of an alternative system and whether or not it is sustainable especially in an economic sense it is helpful to analyze the whole system in terms of its energy costs and its yields per labor input costs Pimental 1984 has done this for corn wheat and potatoes comparing conventional with types of organic systems Table 3 Table 3 An energy analysis of conventional and organic agricultural J J quot Energy Ef ciency Yield Per Labor Input System kcal outputkcal Mg outputlabor hour input Corn Conventional 447 0834 Organic manure 734 0535 fertilization Spring Wheat Conventional 238 0422 Organic manure 349 0314 fertilization Potato Conventional 128 0943 Organic manure 120 0367 fertilization ENTOM558 Lect 103105 Benefits Regsdoc Page 14 of 29 ENTOM 558 Pesticide Topics Fall 2005 1 Conventional systems were assumed to use pesticides and synthetic sources of nutrients equal fuel usage ie gasoline diesel electricity was assigned to each system G In conclusion pesticide technology is here to stay even with the coming of sustainable systems But to be compatible pesticides and fertilizer use must have certain environmental characteristics Thus we must study in detail the environmental chemistry and toxicology of these tools so that we can make improvements and allow their safe use over the long term VIII References Chandler J M 1991 Estimated losses of crops to weeds Estimated losses of crops from plant pathogens CRC Handbook of Pest Management in Agriculture 2nd ed vol I Pimentel D Ed CRC Press Inc Boca Raton Pp 53 68 Hayes W J Jr and E R Laws Jr 1991 Handbook of Pesticide Toxicology vol 1 Academic Press Inc James W C P S Teng and F W Nutter 1991 Estimated losses of crops from plant pathogens CRC Handbook of Pest Management in Agriculture 2nd ed vol I Pimentel D Ed CRC Press Inc Boca Raton Pp 15 51 Knutson R D C R Hall E G Smith S D Cotner J W Miller 1993 Economic impacts of reduced pesticide use on fruits and vegetables American Farm Bureau Research Foundation 123 pp Leng M L 1991 Consequences of re registration on existing pesticides pp 27 44 in Regulation of Agrochemicals A Driving Force in their Evolution G J Marco R M Hollingworth and J R Plimmer eds Am Chem Soc Washington DC Metcalf R L and W H Luckmann 1975 Introduction to insect pest management John Wiley amp Sons NY National Research Council 1989 Alternative Agriculture National Academy Press Washington D C Pimentel D G Berardi and S Fast 1984 Energy efficiencies of farming wheat corn and potatoes organically Organic Farming Current Technology and its Role in a Sustainable Agriculture American Society of Agronomy Special Publication Number 46 pp 151 161 Pimentel D et al 1993 Assessment of environmental and economic impacts of pesticide use pp 47 84 in The Pesticide Question Environment Economics and Ethics Pimentel D and H Lehman ed Chapman amp Hall NY Racke K D 2003 Development and registration of pesticides with reduced risk characteristics Pp 322 333 in Chemistry of Crop Protection Progress and Prospects in Science and Regulation G Voss and G Ramos Ed Wiley VCH Germany Stern V M R F Smith R van den Bosch and K S Hagen 1959 The integrate control concept Hilgardia 2981 101 Taylor C R 1995 Economic impacts and environmental and food safety tradeoffs of pesticide use reduction on fruit and vegetables The Department of Agricultural Economics and Rural Sociology Auburn University AL 21 pp ENTOM558 Lect 103105 Benefits Regsdoc Page 15 of 29 ENTOM 5 58 Pesticide Topics Fall 2005 Ware G W 1983 Pesticides Theory amp Application W H Freeman amp Co San Francisco pp 1 1 Zilberman 13 D A Schmitz G Casterline E Lichtenberg J B Siebert 1991 The economics of pesticide use and regulation Science 253518 522 Part 2 Pesticide Regulations IX History of Pesticide Regulations reference Johnson J M and G W Ware Pesticide Litigation manual Clark Boardman Company Ltd New York gt Regulation of chemicals to protect the public from exposure has been traced back to the mid 1800 s 1863 An Act for the More Effectual Condensation of Muriatic Acid in Alkali Works in England In the US the Pure Food amp Drug Act 1906 the Meat Inspections Act 1906 and the Insecticide Act 1910 were early statutes aimed at che 1 N micals and health concerns However these acts really prevented consumer fraud and protected the legitimate manufacturers of pesticides originally called economic poisons and drugs The Acts prevented the manufacture or transportation of adulterated or misbranded pesticides and drugs within the United States or its territories a They did not provide for registration of products nor testing requirements However the Pure Food and Drug Act was intentioned to protect health b The Acts did require specific labeling information namely it prohibited false or misleading information on labels The Insecticide act required specific label information for some categories of pesticides ie those that contained arsenic the amount had to be stated furthermore inert ingredients had to be stated 1 Some recognition of environmental effects was contained in a provision that stated a product was considered adulterated if it was intended for use on vegetables and yet proved to be injurious to those vegetables The Insecticide Act was little used there were hardly any commercial pesticides available These acts were forerunners of respectively the Federal Food Drug and Cosmetic Act FFDCA 1938 and the Federal Insecticide Rodenticide and Fungicide Act FIFRA 1947 B The Pure Food and Drug Act and the Insecticide Act functioned in parallel to regulate pesticide products and in a rudimentary way protect human health from adulterated foo 1 ENTOM558 Lect 103105 Benefits Regsdoc ds Both the Pure Food and Drug Act and the Insecticide Act had relied on designation of products as misbranded or adulterated to keep inefficacious or undesirable products out of the market a An unanticipated issue raised by the Pure Food Act was determining when or at what level treatment with a pesticide rendered a food product adulterated b There was an early recognition that pesticides could render a food unsafe but there was no mechanism for removing that food from the marketplace 1 The Secretary of Agriculture in order to prove that a food treated with a pesticide was adulterated had to prove the food was injurious to health However pesticide residues did not cause acute injury at the time Page 16 of 29 ENTOM 558 Pesticide Topics Fall 2005 a Even today residues that are above the so called tolerance or standards for legal sale are extremely unlikely to cause an acute adverse response b Furthermore pesticides were recognized as being necessary to the production of crops 2 Thus the two acts were actually in conflict Pure Food amp Drug Insecticide Act Prohibit Misbranding and Adulteration Health Protection lt7Lgt Ensure Efficacious Product Adulteration Standard Placed the Laws in Conflict Figure 7 Conflicting objective of the two original laws covering pesticide use c To remedy the dilemma the FFDCA 1938 provided that a food was adulterated if any amount of poisonous material including pesticides were present However a food was not considered adulterated by a pesticide if the pesticide was required for its production thus was born the concept of benefit versus risk In such a case the Administrator of the Food and Drug Administration FDA was authorized to establish tolerances or legal permissible levels of pesticide residues Consider whether the state of the art of analytical chemistry would have even been able to detect residues at this time 2 The tolerances were supposed to be maximum legal residues although they were supposed to be developed to ensure safety we will discuss how they are not really safety standards when we talk about how tolerances are developed in the lecture on food residues and dietary exposure d The FFDCA was impractical and never worked well Between 1939 and 1947 the year FIFRA was passed only one tolerance was established for fluoride based pesticides on apples and pears and was challenged in court However in the 1920 s concern about lead arsenate residues on apples led to the establishment of a tolerance for export to markets in Great Britain 1 Although the numbers of pesticides began exploding during WWII too little was known about them to even set tolerances for safe levels C The growing number of new pesticides which were very effective but whose risks were unknown presented a dilemma In this atmosphere Congress began work on FIFRA which was passed in 1947 with great support from the manufacturers and users Figure 8 1 FIFRA repealed the Insecticide Act ENTOM558 Lect 103105 Benefits Regsdoc Page 17 of 29 ENTOM 558 Pesticide Topics Fall 2005 N Rodenticides and herbicides were also covered as well as insecticides and fungicides Pesticides had to be registered with the Secretary of Agriculture Each pesticide sold must include specific label or package information a This is the heart of the law requiring name and address of manufacturer an ingredient statement and directions for use which were adequate for protection of the public b Assumption that an adequate label would allow safe use 5 Did not impose testing requirements neither for efficacy or safety however the Secretary could request a full description of all tests if he felt they were needed a Secretary could register a product under protest b Secretary could cancel a product if he felt it was necessary to protect the public 6 The main effect of the law was to allow USDA to track pesticides ie keep an adequate inventory 7 Governed pesticide regulation until 1972 when the law was significantly overhauled PEA Historically Parallel Regulations Pure Food amp Drug Act InseC jde A 1906 1910 Federal Food Drug amp Cosmetic Act FFDCA1938 Federal Insecticide Fungicide amp Rodenticide Act FIFRA1947 reSIdue tolerances registration labelling Figure 8 The parallel nature of pesticide laws and their main objectives U Note that health concerns were left under the jurisdiction of the FFDCA thus FDA rather than USDA following FIFRA the FDA began to develop tolerances for pesticides on food crops Figure 8 1 Evidence for establishing tolerances were taken at public hearings 2 Unworkable system the first tolerances were not actually established until 1955 3 New law was being drafted to improve process first draft required manufacturers to prove safety which brought great protest Law finally amended in 1954 Miller Amendment essentially required health and safety data to be analyzed before a pesticide could be used on a food crop such data would be used to develop the tolerance Figure 9 a The intent of the law was to withhold registration until the tolerance was established thus although the Miller Amendment did not modify FIFRA its effect was to tie together two laws for regulation of pesticides 1 A manufacturer who had registered or sought to register a pesticide under FIFRA for use on food crops was required to obtain a certificate of usefulness from the Secretary of Agriculture and then to petition the Secretary of Health 4 ENTOM558 Lect 103105 Benefits Regsdoc Page 18 of 29 ENTOM 558 b Pesticide Topics Fall 2005 Education and Welfare to establish a tolerance for pesticide residue or to exempt the substance from compliance 2 Petition had to contain a Name and chemical composition of pesticide b Application procedures c Data from investigations on safety d Results of residue testing e Methods for removing excess residue f A proposed tolerance and other grounds in support of the tolerance 3 A y food sold containing residue in excess of tolerance was deemed adulterated Both FIFRA and Miller Amendments passed with consensus of manufacturers agricultural interests and the public 5 In 1958 FFDCA was amended again by the Food Additive Act containing a provision known as the Delaney Amendment Figure 9 The law s intent was to regulate food additives purposefully added to foods ie processed foods Pesticides were exempted as long as they did not concentrate during processing ie to levels above the tolerance for the raw agricultural commodity which was established under the provisions of the Miller Amendment If the pesticide residues did concentrate a processed food tolerance would be required under the provisions of the a ENTOM558 Lect 103105 Benefits Regsdoc Food Additive Act However the Delaney Amendment in the Food Additive Act stated that an additive cannot cause cancer in laboratory animal testing in which case it would not be permitted If a pesticide was deemed oncogenic then it also could be regulated under the Delaney clause In other words as the law was written an oncogenic pesticide could not have a processed food tolerance if one was needed as a result of residues concentrating to levels above the raw food tolerance So a paradox was created called by the National Academy of Sciences the Delaney Paradox an oncogenic pesticide could obtain a raw agricultural commodity tolerance and be used widely but the residues could not legally be present in processed food 1 To get around this paradox the EPA had chosen to use de minimis risk which is a negligible risk defined as no more than 1 in a million excess cancers in the population Page 19 of 29 ENTOM 558 Pesticide Topics Fall 2005 Historically Parallel Regulations Pure Food amp Drug Act Insef Cide Aft 1906 1910 Federal Food Drug amp Federal Insecticide Fungicide amp Rodenticide Cosmetic Act FFDCA1938 Act FIFRAJQ47 Miller Amendment 1954 Food Additives Amendment Delaney Clause 1958 Figure 9 Important amendments that overhauled the FFDCA 6 The Delaney Amendment was rescinded recently with the passage of the Food Quality Protection Act during August 1996 discussed below E After passage of FIFRA many state legislatures enacted their own pesticide laws mostly regulated use rather than manufacture and sale F The regulation of pesticides tool place by the overlapping of responsibilities of two federal agencies Opinion in the early 1960 s held that the laws were ineffectively administered President Kennedy had appointed a commission to study the need for revisions to the laws prior to public interest stirred by Silent Spring Concern over environmental effects also began to be voiced prior to publication of the latter book G By 1969 Congress commissioned a study of the effect of pesticides on the environment the study group was known as the Mrak Commission 1 One of the first results from the study was the removal of pesticide regulation responsibility from the USDA to the new EPA created in 1970 under the Nixon administration H DDT had really been the center of the storm of controversy over pesticide use during the 1960 s this controversy probably spawned the major overhaul of FIFRA known as the Federal Environmental Pesticide Control Act of 1972 FEPCA 1 FIFRA became an environmental statute manufacturers were required to demonstrate that a product could be used without unreasonable adverse effects on the environment ENTOM558 Lect 103105 Benefits Regsdoc Page 20 of 29 ENTOM 558 Pesticide Topics Fall 2005 E Shared Responsibilities j FFDCA Amended FIFRA Foodamp DrugAdminFDA USDA EPA 1970 Federal Environmental Pesticide FDA Control Act FEPCA 1972 food residues Figure 10 Creation of the EPA to oversee pesticide law and major overhaul of FIFRA to address environmental concerns of pesticide use 1 Provisions of FEPCA 1 New requirement for registration and reregistration of all products within four years this deadline never met law amended again in 1978 to set new deadlines and several times thereafter a An applicant for registration had to show that the pesticide would perform its intended function without unreasonable adverse effects on the environment 2 Use of any registered pesticide in a manner inconsistent with its labeling became a crime 3 New system of classifying pesticides restricted vs general use a Restricted use pesticides designated as one which could cause unreasonable adverse effects on the environment including injury to the applicator if additional regulatory restrictions were not imposed 1 Under this system only certified applicators could apply restricted use pesticides 2 This provision necessitated implementation of training and certification programs by the states largely accomplished through universities in programs known as Pesticide Applicator Training PAT b General use pesticide could be sold to the general public for ex in supermarkets nurseries etc without a requirement for licensing or certification J The re registration process was observed to be a failure by 1988 over 600 active ingredients required reregistration In 1988 FIFRA amended again under Reagan requiring completion of reregistrations by 1997 Products included in the process were those registered prior to 1984 1 Reregistration rationale a Historically required but never carried out by USDA b Pesticides registered prior to 1984 met different set of safety standards and testing c Need for institution of GLPs Good Laboratory Practices for tracking data validity ENTOM558 Lect 103105 Benefits Regsdoc Page 21 of 29 ENTOM 558 Pesticide Topics Fall 2005 1 This provision of testing raises the costs significantly It is essentially a sophisticated book keeping system requiring documentation of literally every facet of a lab and field testing operation 2 The need for GLPs grew out of a testing scandal in the late 1970 s when Industrial Biotest a Chicago testing company that conducted many of the animal toxicity tests for manufacturers products was found to have committed very serious fraud in reporting of test results as well as mistreatment of lab animals and assorted bad practices 2 Components of re registration a Updating of the database EPA was to prioritize information needs Consideration was given to pesticide use on food or feed crops whether use could result in contamination of groundwater fish or shellfish whether there were missing data or whether farm worker exposure was likely 1 Thus EPA had to determine the current data requirements and ensure data were available b The data available had to be re evaluated against current safety and testing criteria and then EPA had to make determination of need for registration changes c After the evaluation process EPA could require a modification in label or cancellation of product 1 Note that when a pesticide is granted a tolerance and prior to registration a label is drafted to accompany the product 2 The pesticide label has information about the active ingredient legal uses crops sometimes specific pests rates of application personal protective equipment worker protection restrictions on use no drift no application near water and proper disposal 3 Violation of provisions on the label is a crime d Companies had to submit new data as required by EPA they had 4 years with an extension possible to conduct new studies if needed K Note that other environmental laws like the Clean Water Act and the Safe Drinking Water Act affect pesticides but these have a different legislative history and could be invoked when pesticide residues in water exceed certain standards or if an industry manufacturing or using pesticides needed to discharge wastewater X The Food Quality Protection Act of 1996 FQPA access the law at httpww In 39 quot 391fnnal A In 1993 the National Academy of Sciences released a report commissioned by Congress in the late 1980 s The report Pesticides in the Diet of Infants and Children became the blueprint for amendments to FIFRA and the FFDCA 1 The NAS report concluded that infants and children were not as well protected as adults by the current pesticide regulations Thus the Academy recommended changes in exposure analysis and more focus on the types of foods eaten by kids It also recommended that other exposures besides food be aggregated B The FQPA was supported by both industry and environmental advocacy groups because its provisions were designed to eliminate balancing of risks and benefits and make pesticide regulation entirely risk based as were other laws regulating environmental N ENTOM558 Lect 103105 Benefits Regsdoc Page 22 of 29 ENTOM 558 Pesticide Topics Fall 2005 contaminants Furthermore protection of children and infants would take center stage In return industry wanted the repeal of the Delaney amendment 1 2 With elimination the Delaney amendment all food tolerances would be unified In other words no distinction would be made between raw and processed commodities Also residues of putative carcinogenic pesticides would be permitted as long as they met the standard of negligible risk As a matter of fact the negligible risk standard applied regardless of the perceived health and environmental effects C Although the FQPA really amends both FFDCA and FIFRA simultaneously the most important provisions from our perspective is how risk will be determined How risk is determined is directed by new definitions in the law See Figure 11 for summary graphic of the interaction of the FQPA with FIFRA and FFDCA 1 N Before the FQPA the law dictated that tolerances would be set to protect public health The FQPA says that tolerances will be safe ie a reasonable certainty that no harm will result from aggregate exposure Thus all pathways of exposure food water residential home garden and lawn use would be aggregated together a Aggregate exposure includes exposure of a specific pesticide to all media air water soil as well as food A safe tolerance considers the following factors in addition to aggregate exposure a Exposure of infants amp children and whether they are more susceptible to the effects of a pesticide b Threshold vs non threshold effects ie is the pesticide a carcinogen carcinogens according to EPA logic have no thresholds The potential for disruption of the endocrine system Cumulative exposure 1 Requires that food containing residues of multiple pesticides with the same mechanism of toxicity be added together in considering the amount of exposure oo D When we discuss dietary exposure of pesticide residues we will discuss how EPA ensures safety for pesticide residue exposures FIFRA FFDCA 1947 1938 FEPCA Miller 1954 l 1972 Delaney 1958 Risk Assessment gtToerance M RL l Labelling Registration Figure 11 Relationship of FQPA to FIFRA and FFDCA FQPA has a profound effect on risk ENTOM558 Lect 103105 Benefits Regsdoc assessment policy that in turn affects tolerance setting and labeling Page 23 of 29 ENTOM 558 E TU ENTOM558 Lect 103105 Benefits Regsdoc Pesticide Topics Fall 2005 1 Brie y safety is determined from the various mammalian toxicology tests for acute and chronic toxicity see testing requirements below 2 In these tests the most sensitive toxicological endpoint ie the adverse biochemical or physiological effect occurring at the lowest tested dose is chosen For this endpoint the dose causing no effect No Observable Adverse Effect Level NOAEL is determined 3 The NOAEL is divided by an uncertainty factor 100 if no extraordinary child sensitivity noted or 1000 if child sensitivity noted to obtain a reference dose RfD given in units of mgkg day Any exposure s due to residues from food water or residential use must not exceed the RfD Consequences of the FQPA 1 The FQPA mandated that all pesticide tolerances be reassessed under the new requirements for children s sensitivity endocrine disruption aggregate exposure and cumulative exposure a In 1996 there were about 10000 pesticide tolerances EPA was given until 2006 to complete the assessments After EPA completes a draft re assessment ie risk assessment to determine whether exposure exceeds the RfD then the agency issues a Re registration Eligibility Decision document RED 1 REDs are available on the WEB at httpww mm 39 quot 39 39 39 r cuisi quot M111 2 EPA chose to examine organophosphate OP insecticides first and then to tackle sol called carcinogenic pesticides 3 OPs were surmised to have the greatest potential for exhibiting differential effects on children ie children more sensitive at a given dosage mgkg body weight than adults 4 As a result of the reassessments uses have been cancelled or restricted For example a Chlorpyrifos in the urban use formulation of Dursban will be completely off the market by 2003 b Diazinon will no longer have urban uses c Methyl parathion uses was cancelled for orchard fruits Secrets of the FQPA 1 The FQPA was written as a consumer protection law with no attention to worker exposure and risk nor ecological effects and risk 2 However during the re registration process ie the process of reassessing the safety of the tolerance and development of the RED EPA does examine worker exposure and ecological effects 3 Thus EPA during the reassessment process can require changes in pesticide use characteristics to protect worker and ecological health 4 Indeed late during 2000 EPA was sued by a coalition of advocacy groups headed by National Resources Defense Council NRDC for failure to fully implement the FQPA especially the provisions for cumulative exposure and risk assessment a In the court sanctioned consent decree the EPA is directed to specifically tend to worker exposure and ecological effects issues in addition to the statutory requirements of the FQPA 9 44 Page 24 of 29 ENTOM 558 Pesticide Topics Fall 2005 XI A New Twist Affecting Pesticide Regulation The Coming of Age of the Lawsuit A Over the last 25 years EPA has been a frequent target of lawsuits over a perception that it has failed to live up to the statutes imposed by Congress Indeed one the major impetus behind the FQPA and industry s support of it grew out of a lawsuit that would have likely forced EPA to suspend registration of any earmarked carcinogenic pesticides on raw agricultural commodities if these compounds were also subject to tolerance suspension by virtue of Section 409 of the FFDCA regarding the Delaney Amendment prohibition against carcinogenic pesticide residues in processed food Two sets of lawsuits have impacted pesticide use 1 The Federal Court for District 9 based in San Francisco ruled that aquatic applications of pesticides were subject to jurisdiction as point source contaminants under the Clean Water Act a Thus aquatic pesticide applications for example for irrigation canal weed control need to obtain a National Pollution Discharge Elimination System Permit 2 A lawsuit in 2001 by the WA Toxics Coalition accused EPA of violating the Endangered Species Act by not consulting with the National Marine Fisheries Service with regard to listed threatened and endangered runs of salmon in the Pacific Northwest see Felsot A S 2003 Salmon stimulated lawsuits Swimming in circles or shouldered on sound science Agrichemical amp Environmental News February issue no 202 14 pp httpaenewswsuedu a Although EPA lost the lawsuit in Western WA District Federal Court the agency is now defending itself against a motion for injunction to force it to mandate specific fixed no spray buffer zones around aquatic habitats P3 0 XII Tests Required Under Current Law Code of Federal Regulations 40 Part 158 A Details about the specific testing requirements can be downloaded from the EPA web Site 1 Human Health OPPTS Test Guidelines Series 870 Health Effects httpwwwepa ovdocsOPPTS Hm 39 070 Health Effects Test C 39J quot Series 2 Ecological Fate amp Effects OPPTS Test Guidelines Series 850 Ecological Effects httpwwwepa ovopptsfrsOPPTS Hm 39 0 F 39 Effects Test Gui delinesDrafts B Number amp Kind of Studies Required for Registration classification according to Leng M L 1991 Consequences of reregistration on existing pesticides pp 27 44 in Regulation of Agrochemicals A Driving Force in their Evolution G J Marco R M Hollingworth and J R Plimmer eds Am Chem Soc Washington DC Product chemistry 26 Mammalian toxicology 27 Wildlife toxicity 27 Toxicity to nontarget organisms 15 Environmental fate 24 Drift 2 Residue in crops amp analytical method 18 Q P PP PB ENTOM558 Lect 103105 Benefits Regsdoc Page 25 of 29 ENTOM 558 Pesticide Topics Fall 2005 C Specific provisions of the 1988 amendments to FlFRA requiring data for registration ie data requirements as listed in the Code of Federal Regulations 1 product chemistry a Active ingredient b Impurities 1 Some impurities may be toxicologically important for ex isomalathion an isomer contaminant is about 5 times more toxic than malathion a malathion LD50 gt 2500 mgkg b isomalathion LD50 lt 500 mgkg S O o O CH3OII n CH3SII P S CH C OQHS P S CH OC2H5 CH3O I CH3O I CH OCZHS CH OCZHS O O malathion isomalathion c Analytical method for active ingredient d Certifiable concentrations e Physical amp chemical characteristics 1 Useful for defining necessity for other studies a high partition coefficient could indicate bioconcentration potential b vapor pressure is a consideration in setting worker reentry intervals c viscosity amp miscibility is important to setting acceptable labeling for tank mix and spray applications f Production process g Formulation process h Dupont has been fined by EPA for a Benlate fungicide formulation contaminated with the herbicide atrazine even though it is not clear that the contamination actually caused crop damage or the contaminant even existed in the stocks that were used Pesticide amp Toxic Chemical News Oct 5 1994 2 Residue chemistry a Used to estimate exposure of general population to pesticide residues in food b Used to set and enforce tolerances c Information required Chemical identification and composition of product Amounts frequency and timing of application Amount of residues remaining on food Analytical method adequate for enforcement a Note that the analytical method developed for analyzing active ingredient content in a formulated product may be very different ie simpler than the analytical method needed to analyze for environmental residues 5 Practical method for removing excess residues 3 3 Environmental fate a a Generic studies required PENN ENTOM558 Lect 103105 Benefits Regsdoc Page 26 of 29 ENTOM 558 Pesticide Topics Fall 2005 1 Degradation 2 Metabolism 3 Mobility 4 Dissipation 5 Accumulation b Rationale 1 Used to assess toxicity to humans through exposure to residues remaining after application either in treated areas or from consuming contaminated food 2 Used to assess the presence of widely distributed and persistent pesticides in the environment which may result in loss of usable land water or wildlife resources 3 Used to assess potential exposure of nontarget organisms like fish and wildlife 4 Used to estimate expected environmental concentrations in specific habitats where threatened or endangered species are found Practical significance 1 Availability of residues to rotational crops 2 Irrigation water might contain residues 3 Setting of realistic field reentry intervals 4 Protection of potable water supplies 5 Workers may be exposed to degradation products 4 Hamrds to humans amp domestic animals a Acute toxicity 1 Defines hazard of handling product can answer questions of how hazardous dermal exposure is in relation to oral or inhalation exposure 2 LD50 measurements by various routes of exposure b Subchronic toxicity 1 Helps define doses to be used for chronic toxicity 2 looks at range of effects that might occur from doses that are not acutely toxic but occur repeatedly over a limited time frame 3 Usually a 90 day study c Mutagenicity 1 Assess potential to affect the cell s genetic material using a battery of different tests 2 Compounds that damage DNA directly represent true hazards of carcinogenicity likely to be dropped from further development 3 Findings of mutagenic potential can be used to assess heritable effects oncogenicity or other health effects d Chronic toxicity 1 Life time feeding studies using maximum tolerated dose 2 Endpoint is usually carcinogenicity actually tumorigenicity although other effects are measured Teratogenicity birth defects Reproductive effects effects on fertility 0 run ENTOM558 Lect 103105 Benefits Regsdoc Page 27 of 29 ENTOM 558 X111 B C D ENTOM558 Lect 103105 Benefits Regsdoc 5 0 8 Pesticide Topics Fall 2005 1 These are multigenerational studies the pregnant rat is fed the pesticide mixed into the diet effects on offspring are measured ability of offspring to successfully mate and reproduce are also examined g Metabolism 1 Aids extrapolation of data from animals to humans 2 Development of poisoning antidotes h Note that under mammalian toxicology we would now include endocrine disruptor screening studies Field reentry protection studies a Monitoring data under actual exposure conditions b Combined with data from studies of toxicity and residue dissipation c Practical significance occupational exposure is the highest risk for health hazards Pesticide spray drift evaluation a Measure droplet size spectrum using formulations b Drift evaluation under field conditions c Practical significance precautionary labeling to protect nontarget crops Hamrds to nontarget organisms a Determination of pesticidal effects on birds mammals fish terrestrial and aquatic invertebrates and plants b Tests include short term acute subacute reproduction simulated field and full field studies c Testing is hierarchical or tiered if tests lower in the tier indicates a problem then the next test in the tier will be performed progression is from basic lab tests on one end to applied field tests on the other end d Toxicity information is compared with measured or estimated pesticide residues in the environment to assess potential impacts and decide whether further studies are warranted 6 Long term field studies which include reproductive life cycle and plant eld studies may be required if predictions of possible adverse effects in less extensive studies ie lower in the tier cannot be made or when the potential for adverse effects is high Product performance a Ensures that pesticide products will control the pests listed on the label b Unnecessary pesticide exposure to the environment will not occur as a result of the use of ineffective products c Includes specific performance standards to validate the efficacy of pesticides used in the public health area eg disinfectants rodenticides Costs of Pesticide Development and Registration A RampD costs have been estimated to be over 70 million Reregistration Fee estimated at 150 000 per product ie not active ingredient but formulated product does not include cost of any new studies that may be required Product maintenance fee estimated at 35000 Economics of pesticide development and marketing Leng 1991 Page 28 of 29 ENTOM 558 Pesticide Topics Fall 2005 1 It may take 15 years from discovery for a pesticide product to attain a positive cash ow by year 20 after discovery the patent would have expired the patent is usually obtained around 3 years after discovery of a new product ENTOM558 Lect 103105 Benefits Regsdoc Page 29 of 29 ENTOM 558 Lecture 103105 Part II WASHINGTON STATE 13 UNIVERSITY Allan Felsot Department of Entomology WSUTC Food amp Environmental Quality Lab afelsottricitywsuedu Experimentation measurement dAata analysis Scienti c Risk Assessment A Sociopolitical Economic Risk Management 1 Determination of the potential hazards of a substance and the probability that it will cause harm to the environment andor human health when used in the manner for which it is intended a Hazardpotential harm conditional a Risk Probability of Harm Can never be zero 1 Determination of what should be done to avoid minimize or mitigate a risk Determ nat on of acceptab e rsk Eva uat on of a ternat ve rsk contro act ons Se ect on among a ternat ves Maybe do nothing Imp ement act ons Based on Consideration of Politics Economics Ethics amp Hopefully Science ill Narrative Standards Statement of des red object ve or goa in Numerical Standards MCLs Max mum Contam nant Leve s Amb ent Water Qua ty Crter a it Acceptable Margins of Exposure MOE Reference Doses Rst Popu at on Adjusted Doses PADS Leve s of Concern LOCs Risk Assessment Toxicology Environmental Chemistry 1 1 No Observable Exposure Adverse Effect Level Assessment it Hazard Identification What are the relevanttoxicity endpoints it Doseresponse relationship What is the population response relative to magnitude of dose and frequency and duration of exposure 3 Exposure assessment What is the distribution of environmental residues How much does a person contact i Risk Characterization Can be ca cu ated object ve y as exposure re at ve to some defined tox co 09 ca endpo nt For ex calculate a margin of exposure MOE the ratio of the dose causing no effect to the estimated or actual exposure level However whether the rat 0 MOE s judged acceptab e or unacceptab e depends on rsk management object ves in Endpoints Death System c tox c ty organt ssue patho ogy Adverse Deve opmenta Outcomes Adverse Reproduct ve Outcomes Cancer excess rat tumors Subt e Enzyme Changes Caution these may only indicate exposure and not a physiologically adverse effect 3 Herbicides Most likely systemic toxicity Not neurotoxic At high doses cause organ amp tissue pathologies it nsecticides OPs and Carbamates Most likely inhibition of plasma cholinesterase No systemic toxicity at doses inhibiting ChE After the hazard is identified e the tox co 09 ca endpo nt of concern s chosen Then the next step is to determine how the magnitude of the response varies with increasing concentrations or doses Population Response to Increasing Doses of Substance 50 Respo se Numbers Responding Dose mgkg Dose Makes the Poison 100 Population Response Cumulative 50 D50 39 ED50 OOU Dose mgkg in Reference Dose RfD A dose w th reasonab e certa nty of no harm after s ng e exposure or fet me exposure Acute RfD Chronic RfD NOAEL 100 Reference Dose RtD in Population Adjusted Dose If feta neonata rats are more sens t ve to g ven dose than mother or there are neurobehav ora deve opmenta or reproduct ve effects w thout effects on adut at a g ven dose Then an extra safety factor s app ed to RfD Rf D Population Adjusted Dose PAD 10 Aggregate Exposure amp The Shrinking Risk Cup FQPA Risk Cup w Old Risk Cup FQPA Risk Cup Child Endocrine Cancer Hazard Home amp Lawn Vater in Herbicides Nil dietary exposure Drinking water exposure likely Corn Belt Residential exposure likely in Insecticides Dietary exposure likely Drinking water exposure unlikely Residential exposure likely Exposure X100 lt 100 RfD or PAD in Part Science D v de the exposure eve by the close observed to cause no effect State the rat 0 it Part Risk Management D vde the exposure eve by the eve of exposure believed to be safe Determ ne f the rat 0 s acceptable or not DIETS 0F INFANTS c AND CHIlDREN it nfantschildren with greater surface area to body mass ratio than adults i Brain size in infants amp children proportionally greater relative to body mass it Fetal brain rapidly developing laying down new nerve connections especially in the third trimester of pregnancy Rapid growth during the first year after birth Dependence of connections on AChE perhaps ACh also Blood brain barrier less developed not as impermeable ii ii iiw ii Dose Makes the Poison is often invoked to explain why high doses are hazardous but low doses are innocuous Timing of the dose however is as important as the dosage itself fl For consideration of effects on infants amp children fetal development and early post natal life are considered the most vulnerable stages for toxication However even within the different stages of fetal development there are certain periods that are more critical than others Ventilation breathing rate significantly greater in infants than in adults Greatervolume of airperunit time 3k Filtration of blood through kidneys renal clearance slower in infantsthan in adults it Enzymes known to detoxify chemicals may be at lower levels in infants amp children than in adults Behavioral differences nfants amp children on the ground more often Much handto mouth contact Em External quotaim Pllnuhll alum Selevan et al EHP 108 S1451 2000 icThe new unifying paradigm for all adverse health effects Our Sto en Future Theo Colborn et al 1996 Near y every adverse effect mag nab e t ed to an effect on the endocr ne system in One of three nterdependent commun cat on systems of the body that regu ate growth deve opment phys o 09 ca processes and behav or Nervous System ARE WE THREATENINE IJLIR lNTELLlBENBE AND SURVIVAL7 A SEIENTIFIE DETEETIVE STEIRY llli THEI EDLBDRN DIANNE DUMANIJSKI ANI JEIHN PETERSEN MYERS Each system is organized as specialized tissues glands and organs Communication between systems by secretion of chemical messengers in Messengers bind to receptors in target cells causing a response in Builtin controls called feedback loops regulate over or under secretion of messengers f Tii i liiiill imiv ii L in Endocrine System Hormones in Nervous System Neurotransmitters in Immune System Cytokines How Hormones Work Receptor Binding gtProtein Synthesis Cell Cytoplasm Nucleus gt Rec eptjor protein synthesis Estrogen Testosterone it Gonads i Gonads Uterus in Secondary Sex w Vag na Organs in Breasts prosme seminal ve3icles in Heart penis 31 P m tall gt5 P tu tary in Bra n in Bra n iSynergism among low levels of pesticides 3 Relationship between breast cancer and DDT in Morphological abnormalities in male genitalia it Sperm decline ti Bear in mind cancer is rare especially in childhood Some concern about increasing brain cancers and leukemia However trends seem to have leveled 3k Animal testing MTD maximum tolerated dose testing Linearassumption i Epidemiology No39ThreShOId Observed Data Incidence of Tumors Threshold Dose mgkgday gt Although animal models have shown that cancer risk can be increased after exposure to certain potentially hazardous agentspreconceptionally in utero and perinatallyin humans much ofthe evidence is equivocalquot it This is partly because findings from studies that have investigated the etiology of cancer in relation to prenatalearly life exposures are often based on small numbers of cases because both cancer in young people and many of the potentially hazardous exposures studied are rarequot Anderson et al EHP 108 573 2000 25 000 Disease in Unexposed 20 w 20 000 0 1 u 1 I 15 000 O S 8 10 000 5 000 0 2 4 6 8 10 Relative Risk Modified from Anderson et al EHP 108 573 2000 From Anderson et al EHP 108 573 2000 Cohort sizes would have to be impractically large to obtain a significant effect between two exposure populations it Valid diagnostic information is easier to collect than exposure information which is often not collected or unavailable Surrogate information is used Participation rates are often lower among controls causing false positives an negatives on selfreported exposure information i Timing of exposure problematic i Confounding tactors Lifestyle other chemical exposures etc Acquavella et al 2003 it EPA determ ned that these compounds pose the greatest rsk to ch dren most of them in O der stud es show n acute tox c ty tests that juven e or mmature rats more suscept b e it Acety cho nesterase nh bt on 5 common to both adu ts and young in However may be another mechan st 0 r0 e for AChE n fetus that s not operat ona n adut in Neuru at on compete by 1 month n humans Neural plate Neural tube in Neurogenes s pro ferat on it M grat on in D fferent at on in Synaptogenes s it Apoptos 5 gt5 Mye nat on Both acetylcholine and acetylcholinesterase have been found very important to normal nerve development in cell cultures in n vivo studies suggest that either inhibition of AChE or some other interaction with the enzyme at a site distal to the esteratic serine site causes disruption of normal nerve development AChE act39witv DPMIganglinn thnusands D Z 4 E Days in vriru Nauritic outgrowth mm In H Neurileuutgruwth H AChE activity an Bigbee et al 1999 E E 8 50 6 E co B u 40 Cquot 20 0 I l I I 7 6 5 I Molar concentration of BlJV284c51 i ndustry studies submitted to EPA showed no increased sensitivity of immature rats nor fetal rats to CLP EPA agreed Dow did publish its data in refereed journal it EPA decided to apply an increased safety factor of 10X making the RfD a PAD 2k EPA cited published literature from in vitro and in vivo studies that CLP may interact with AChE at a non esteratic site to affect brain development or at least important biochemicals for neuronal differentiation in Both DowAgrosciences and Syngenta agreed to remove chlorpyrifos and diazinon use from the urban markets Manufacturers probably realized that it was going to be difficult to quotprovequot a low enough exposure to these compounds ie an exposure below either the RfD or the PAD when aggregate exposure was taken into consideration


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